Journal of Comparative Physiology A

, Volume 201, Issue 1, pp 5–18 | Cite as

Biomechanics of hearing in katydids

  • Fernando Montealegre-ZEmail author
  • Daniel Robert


Animals have evolved a vast diversity of mechanisms to detect sounds. Auditory organs are thus used to detect intraspecific communicative signals and environmental sounds relevant to survival. To hear, terrestrial animals must convert the acoustic energy contained in the airborne sound pressure waves into neural signals. In mammals, spectral quality is assessed by the decomposition of incoming sound waves into elementary frequency components using a sophisticated cochlear system. Some insects like katydids (or bushcrickets) have evolved biophysical mechanisms for auditory processing that are remarkably equivalent to those of mammals. Located on their front legs, katydid ears are small, yet are capable of performing several of the tasks usually associated with mammalian hearing. These tasks include air-to-liquid impedance conversion, signal amplification, and frequency analysis. Impedance conversion is achieved by a lever system, a mechanism functionally analogous to the mammalian middle ear ossicles, yet morphologically distinct. In katydids, the exact mechanisms supporting frequency analysis seem diverse, yet are seen to result in dispersive wave propagation phenomenologically similar to that of cochlear systems. Phylogenetically unrelated katydids and tetrapods have evolved remarkably different structural solutions to common biophysical problems. Here, we discuss the biophysics of hearing in katydids and the variations observed across different species.


Cochlea Insect hearing Auditory mechanics Impedance Crista acustica 



Acoustic trachea


Anterior tympanal Membrane


Auditory vesicle


Crista acustica


Hemolymph channel


Laser Doppler vibrometry


Posterior tympanal Membrane


Tympanal membrane


Tympanal plate



This work was sponsored by the Human Frontier Science Program (Cross Disciplinary Fellowship LT00024/2008-C to F.M.-Z.). The authors are currently sponsored by the Royal Society, and by the Leverhulme Trust (grant No. RPG-2014-284). The Colombian Ministry of Environment granted a permit for fieldwork at Gorgona National Park (decree DTS0-G-31 11/07). We would like to thank two anonymous referees for discussions and comments on earlier versions of the manuscript. We also thank Ben Chivers for proof-reading the final version on English grammar. All applicable international, national, and/or institutional guidelines for the care and use of animals were followed.


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© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  1. 1.School of Life Sciences, Joseph Banks Laboratories Green LaneUniversity of LincolnLincolnUK
  2. 2.School of Biological SciencesUniversity of BristolBristolUK

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